doriz said:

518 posts in and you still have a misfire

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It still persists.
I've sorted the original nut in the combustion chamber issue, but I now believe I'm chasing the issue, which caused the nut in the combustion chamber in the first place.
Next on my list is the boost pipes to the intake manifold, which are original and not healthy looking.
Don't forget that it was parked up for 2 months, after the rear diff seized, which prevented me from looking at the misfire issue.

I'd forgotten I'd started this thread.

As the engine although running (actually quite well), still isn't perfect. I've decided to sort it again, only properly this time.

It took several months of looking, but a decent replacement head came up for sale. It's a 9000 mile 2015 SD4 head, which came complete with cams, followers, and the important matching bearing ladder!! This head cost me just £310 delivered, which was an absolute bargain. It's just a shame that nothing like this was available, when I actually needed it, but that's the law of sod coming into play.

So as I'm between jobs (I do start a brilliant new job next week), I thought I'd get on with doing the head swap, which I'd been putting off since April, when I got the new head.

So yesterday I started pulling the engine apart again, although thankfully I don't have to take the bottom end apart this time.

Now these DW12 engines aren't for the faint hearted, as they're complicated, with loads of components to get out the way, so the head can be removed.
Even the head requires stripping down, to get at the head bolts.
So it's an absolute nightmare to work on, and being that it's so high of the ground, I need a step stool to get at the back of the engine.

To remove the head, everything needs to be removed.
The timing belt, the engine mounts, the intake manifold, the exhaust manifold, the EGR valve/cooler assembly, the combined low pressure fuel/vacuum pump (it's cam shaft driven), the HP pump (also cam shaft driven), the HP fuel rail, the injectors (I left them connected to the rail to prevent them draining), the starter needs to come off, so the flywheel can be locked in the timing position, and about a million different electrical plugs and harness clips, and the cooling system needs draining too.

As the service is due in 15 days, I'll take the opportunity to change the oil and replace the filter as its is almost impossible to get at with the inlet manifold in place.

I'll also take the opportunity to see how the replacement piston is bedding in, as it was second hand, and I didn't trust the Chinese rings I got for it.

Here's some pictures of the engine as it comes apart.

Gulp! Chinesium cylinder rings? Fingers crossed!

rob_bell said:

Gulp! Chinesium cylinder rings? Fingers crossed!

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When I saw the rings were made in China, I didn't fit them.
I chose to de-glaze the bore, and fit the low mileage replacement piston with it's original rings, which I thought was probably a safer bet.
I knew the rings would take some time to bed in, but thought that better than having a ring fail in use later on.

Yes, most definitely. A wise decision I think

rob_bell said:

Yes, most definitely. A wise decision I think

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If the rings had been made in Europe, then I'd have fitted new ones, but I just couldn't bring myself to use £3 (yes they cost just £3) Chinese rings.

Strange really, as I'd have no issue buying a Chinese built EV, which is what I'm planning in a couple of years.

I think that is the difference between an OEM manufacturer and some unbranded parts that you don't know the source of... could be good, could be a disaster. Not worth the risk in an engine.

rob_bell said:

Not worth the risk in an engine

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That's the way I saw it.
It'll be interesting to see how the replacement piston has bedded in, as it's done about 3k miles since being fitted.

Hi John.
Big task ahead hope all goes well, thank you for the photos as you know they tell and complete a story, how hard was it to raise the injectors easier than on a FL1 or about the same ? a couple look to be rusty and need cleaning up i think, any reason for that do know, EGR worth looking at while you are in there do you think, few questions hope that is ok

Arctic2 said:

Big task ahead hope all goes well

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Thanks. It's giving my a good workout, which I'm feeling at night.

Arctic2 said:

how hard was it to raise the injectors easier than on a FL1 or about the same ?

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The 2 rust free injectors came out pretty easily, as they don't really touch anywhere, except the bottom seat to the head.

Arctic2 said:

a couple look to be rusty and need cleaning up i think, any reason for that do know

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Yes, but I don't know exactly how to clean them yet.
They are very delicate, and shouldn't be knocked, inverted or anything else vaguely damaging.
I might just give them a gentle wire brush and coat them in grease to keep the rust off in future.

Arctic2 said:

EGR worth looking at while you are in there do you think,

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I wasn't going to do anything with the EGR, as I'd blanked it off last time.

Arctic2 said:

few questions hope that is ok

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Not a problem.

Another busy day on the FL2.
The damaged head is off, and the low mileage replacement is back on.
I'm beginning to reassemble all the components that need to come off, to remove the head.
So far I've got the head on, and the bolts torqued up in the 4 stages listed, ending in the silly high torque final rotation. It's not an easy job, requiring a 4ft extension on my breaker bar.

The exhaust manifold is back on, which was easier with the newer design bolts that came with the head.
The thermostat is also back on, again aided by the correct bolts that came with the head.

Annoyingly I've discovered 1 of the new glow plugs I fitted last autumn has failed, so tomorrow I'll pop to the local motor factors to pick up a replacement. I can't fit the inlet manifold, until the glow plug is replaced, as they're impossible to get at with the manifold in place (good design, not), but I'm hoping to get the engine back together on Sunday.
I've also discovered why there's a bit of transmission slack when pulling away. It seems the lower engine mount (does the same job as the FL1 lower tie bar), has failed, allowing the bottom of the engine to move more than it should.

Once the head was off could you tell by the combustion chambers/pistons if one cylinder was running different to the others ?

Andy Warren said:

Once the head was off could you tell by the combustion chambers/pistons if one cylinder was running different to the others ?

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Pictures tell a thousand words, and pictures will follow.
But no, the combustion looks the same across all cylinders, however it is evident that one of the inlet valves on the damaged cylinder (No 2) wasn't sealing correctly, as the inlet port to that valve is covered in soot, which it wasn't when it went together.

Dedication is all it takes.

lynall said:

Dedication is all it takes.

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It's getting plenty of that, and my body is complaining about it too.
I've got aches in places I didn't know I had.

It's nearly back together now though, with just a few covers, the starter and inlet manifold to refit, then refill the coolant, and it's time to test, when hopefully I'll discover all the hard work was worth doing.

Nodge68 said:

It's getting plenty of that, and my body is complaining about it too.
I've got aches in places I didn't know I had.

It's nearly back together now though, with just a few covers, the starter and inlet manifold to refit, then refill the coolant, and it's time to test, when hopefully I'll discover all the hard work was worth doing.

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I reckon you are on the right track if you found soot in the intake valve port.

lynall said:

I reckon you are on the right track if you found soot in the intake valve port.

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Considering the valve seats were really out of round after the nut pounded on them for an unknown mileage, I knew it was touch and go when I fitted the head. I did my best to restore the seat shape, with many hours of lapping, but it obviously wasn't good enough.

I'm hoping for better results with the replacement head though.

He's alive!!

Pictures and video to follow.

Great news. Let's hope the misfire has taken its leave now!!!

andyfreelandy said:

Great news. Let's hope the misfire has taken its leave now!!!

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I've just taken him for a drive, and he's miles better, much more responsive, and definitely more powerful and loads less noise too.

However there still seems to be a slight misfire evident, more like a flutter under 75% power and above, over 2500 RPM.
I'm unsure as to the cause, but I'm going to try the crank position sensor first, as I've read these can cause missing as the revs go up.
It could be an iffy injector too, but I've a good spare which I can substitute 1 by 1 to prove those.

There's also a small amount of air getting in to the fuel intake, which could also be the cause, which is definitely worth investigating.